[TypeScript] explicitly defines call patterns for page method

[dimitropoulos]

I noticed that the type for page previously required all arguments, but this doesn't match the behavior described in the tests or the library itself.

I made what is here by looking at the tests (and not the library source code) because I had quite a hard time thinking through all the combinations the library source code allows (and, after all, the tests already seem to have done that).

[bryanmikaelian]

Thanks for the contribution @dimitropoulos! Changes look fine but it appears your tests are failing. Here is the error message I am seeing when I run make test locally:

1) should accept (name)
     Analytics #page
     Can't find variable: test
/var/folders/tx/34knkw392dj3k7sbj709ggn00000gn/T/test/analytics.test.js:736:0 <- /var/folders/tx/34knkw392dj3k7sbj709ggn00000gn/T/c2c57f9139c4399452aacd0bc52983aa.browserify:35039:25

Once we fix that up, we can merge this!

[dimitropoulos]

should be all set. I will note that calling with just name is, now, the only way to call page this without a callback. Is that correct or is the callback (as a last argument) always optional?

[bryanmikaelian]

@dimitropoulos Ah, the callback is always optional. We'll definitely want the types to reflect that. From our docs

An optional function that is executed after a short timeout, giving the browser time to make outbound requests first.

This is true for any type of call (Track, Identity, etc)